1. Field of the Invention
The present invention relates to an image-transfer medium for ink-jet recording, which is suitable for use in forming an image on a transfer-printing medium such as cloth or film by transfer printing, and an ink-jet image-transfer printing process.
2. Related Background Art
An ink-jet recording method is intended to make a record of images, characters and the like by generating and ejecting droplets of an ink by any one of various ink ejection systems, for example, an electrostatic attraction system, a system in which a piezoelectric element is used to give an ink mechanical vibration or change, or a system in which an ink is heated to form bubbles in the ink so as to use the pressure thus produced, and applying a part or all of the droplets to a recording medium such as paper. The ink-jet recording method attracts attention as a recording system which scarcely produces noise and can conduct high-speed printing and color printing.
In recent years, ink-jet printers, by which full-color printing can be simply conducted as described above, have been spread, and there has thus been an increasing demand for conducting color printing on various media using these printers. In order to meet such a demand, particular attention is paid to printing techniques using a transfer printing system in that printing can be conducted irrespective of the form of recording media, namely, the formation of an image can be performed on any medium which does not permit direct printing by a printer.
Some image-transfer media making good use of an ink-jet recording system, which are used for printing processes through heat transfer or the like, have been proposed to date. For example, Japanese Patent Application Laid-Open No. 8-207426 has proposed an ink-jet recording sheet in which an ink-receiving layer is composed of a thermoplastic resin, a crystalline plasticizer and a tackifier, thereby permitting its sticking by heating alone. Japanese Patent Application Laid-Open No. 8-207450 has proposed an image-transfer medium comprising a base material layer and a heat transfer layer which is composed of a particulate thermoplastic resin, inorganic porous fine particles and a binder and permits ink-jet printing and heat transfer. U.S. Pat. No. 5,501,902 has proposed an image-transfer medium for ink-jet comprising a transfer layer of a structure that a cationic resin, an ink-viscosity adjuster and the like are added in addition to the above-described components.
These image-transfer media according to the prior art have sufficient performance as to formation of an image thereon by ink-jet recording and transfer printing of the image formed thereon. However, the performance as to fastness properties of such images transferred to various transfer-printing media has been yet insufficient. More specifically, when cloth to which an image was transferred from such an image-transfer medium as described above has been washed, the optical density of the image has been deteriorated by causes such as running out of coloring materials and fuzzing at the surface of the cloth having the transferred image.